双对苯醌的抗氧化活性分析及其固体发酵条件优化

为探索生物活性未知的双对苯醌（2,7-dihydroxy-3,6,9-trimethyl-9H-xanthene-1,4,5,8-tetraone，DTXT）的抗氧化活性，并提高其发酵产量，考察DTXT的还原力以及对超氧阴离子自由基、羟自由基、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl，DPPH）自由基的清除效果，在单因素试验基础上，采用响应面法优化了DTXT产生菌瓶生顶孢霉（Acremonium cavaraeanum）CA022菌株的固体发酵培养基。结果表明：在200 μg/mL质量浓度下，DTXT的还原力与芦丁差异不显著，高于VE和2,6-二叔丁基-4甲基苯酚，对超氧阴离子自由基清除率达到67.00%，对羟自由基清除率达到78.83%，对DPPH自由基清除率达到76.53%。通过响应面试验，得到最佳培养基配方为葡萄糖0.773%、硝酸钠0.185%、H3BO3 0.032%、VB1 100 μg/100 g，在此条件下实际获得的DTXT产量为4 150.8 mg/kg，是优化前产量的（2 864.83 mg/kg）1.45 倍。

Analysis of Antioxidant Activity of 2,7-Dihydroxy-3,6,9-trimethyl-9H-xanthene-1,4,5,8-tetraone and Optimization of Solid-State Fermentation Conditions for Its Production

The antioxidant activity of 2,7-dihydroxy-3,6,9-trimethyl-9H-xanthene-1,4,5,8-tetraone (DTXT) was tested by reducing power, superoxide anion (O2-·), 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (·OH) scavenging assays. The medium composition for DTXT production by Acremonium cavaraeanum CA022 in solid-state fermentation was optimized using one-factor-at-a-time method and response surface methodology (RSM). The results showed that the reducing power of DTXT at a concentration of 200 μg/mL was not significantly different from that of rutin, but higher than that of VE and BHT. DTXT could scavenge 67.00% of O2-·, 78.83% of ·OH and 76.53% of DPPH radical. The optimal medium formulation was obtained as follows: glucose 0.773%, sodium nitrate 0.185%, H3BO3 0.032%, and VB1 100 μg/100 g. It gave a DTXT yield of 4 150.80 mg/kg, which increased by 1.45 times compared with that before optimization (2 864.83 mg/kg).